1. Field of the Invention
The present invention relates to an image data producing apparatus for producing image data representative of a proof image in which an image obtained by a printing system is simulated, and an image data producing program storage medium storing an image data producing program which causes a computer system to operate as such an image data producing apparatus when the image data producing program is executed in the computer system.
2. Description of the Related Art
Hitherto, in the event that a printing for an image is performed in a printing system for printing a color image, an operator uses prior to the printing a proofer readily reproducing the image to confirm the finish of the image to be printed in the printing system referring to a proof image produced by the proofer. A function of the proofer to simulate the image obtained in the printing system is implemented by a proofing image data producing apparatus for producing image data representative of such a proof image.
FIG. 13 is a schematic construction view of a conventional proofer and a printing system.
FIG. 13 shows a printing system 2000 and a conventional proofer 1000′. The printing system 2000 comprises a printing halftone dots image data producing apparatus 400, a CTP (Computer To Plate) 500 and a printing machine 501. The printing halftone dots image data producing apparatus 400 receives, for example, multi-tone level image data for C, M, Y, K-plates, and produces halftone dots image data through a halftone dots process for the received multi-tone level image data. The CTP 500 receives the halftone dots image data thus produced and produces a printing plate in accordance with the received halftone dots image data. The printing machine 501 continuously prints halftone dots images on a sheet using the produced printing plate.
The conventional proofer 1000′ comprises a proofing halftone dots image data producing apparatus 100′ and a printer 200. The proofing halftone dots image data producing apparatus 100′ receives multi-tone level image data, which are the same as the multi-tone level image data fed to the printing system 2000, and applies a multi-tone level conversion and a color conversion to the received multi-tone level image data and further applies a halftone dots process to the multi-tone level image data subjected to the conversion, so that proofing halftone dots image data is produced. The printer 200 receives the proofing halftone dots image data thus produced and prints out halftone dots image according to the received halftone dots image data.
The conventional proofer 1000′ performs the color adjustment and the multi-tone level adjustment for the image data in the manner as mentioned above so that a halftone dots image to be printed by the printing system 2000 may be approximately reproduced on a halftone dots image printed out by the printer 200.
However, in general, the halftone dots image printed out by the proofer 1000′ is different, as compared with the halftone dots image printed by the printing system 2000, in a halftone dots pattern which is defined by elements such as angle and interval in a halftone dots arrangement and shape and size of halftone dots. Such a difference in the halftone dots pattern of an image brings about a difference in Rosette pattern and moiré pattern and thereby bringing about impressions of the image in its entirety. Such a halftone dots pattern is determined in accordance with an image data producing apparatus for producing image data representative of a proof image. Thus, there is desired an image data producing apparatus for producing image data representative of a proof image which reproduces an image to be printed in a printing system and a halftone dots pattern as well.